backend: cache backend

In decisionpatterns/cache: Intuitive and Comprehensive Cache

Description

An backend definitions

Usage

backend(name, reader, writer, ext, ...)

## S3 method for class 'backend'
print(x, ...)

backend_ext(backend = cache_backend())

as_backend(x, ...)

## S3 method for class 'character'
as_backend(x, ...)

## S3 method for class 'fs_ext'
as_backend(x, ...)

## S3 method for class 'fs_path'
as_backend(x, ...)

Arguments

name	string; name of backend.
reader	function for reading from the cache
writer	function for writing to the cache
ext	string extension associated with this file without the period.
...	other name-value pairs that are stored as part of the definitions
backend	string; name for backend

Details

A backend is the way cache reads and writes from the cache. This simply collects all the information associated with the backend in one list.

A backend for a cache contains complete details about storing and retrieving files

backend_ext() gives the extensions associated with a backend.

as_backend retrieves the backend based on x. x can be the name of the backend, the extension associated with the backend or a file (with a known extension). In every case, a backend object is returned.

Value

list with subclass backend

A ext() object for the backend

as_backends returns a backend object based on x:

• character : backends named x

• fs_ext : backend with x as its path extension

• fs_path : backend that matches the same extension as the path

See Also

• backends()

• cache::cache_register()

• cache_backend()

Examples

  backend( name="rds", reader=function() NULL, writer=function() NULL, ext="rds" )

  'rds' %>% fs_ext() %>% as_backend() %>% .$name

  'cache/iris.rds' %>% fs_path() %>% as_backend() %>% .$name

decisionpatterns/cache documentation built on June 15, 2020, 9:35 p.m.